IMD predicts normal rainfall, but localized storms show the complexity of forecasting.
The great Indian monsoon comes only once a year, but when it comes, it brings good cheer.
As if on cue, there were heavy thunderstorms in and around Chennai on the day the news appeared. Although unrelated to the southwest monsoon that sets in by June 1 over Kerala, summer showers might just be a harbinger. And yet, unpredicted as it was, the rain showed up the difficulties of reading all the signs and matching the parameters in predicting rainfall, especially over an extended period in a large land mass.
The Indian Meteorological Department, being a wing of government, can be somewhat prone to optimism over something as valuable as rainfall to the country, its crops, its economy and water for 145 crore people, besides its salutary effect on keeping inflation in check. And hence, IMD puts out its annual message of hope, which may not always match reality. Even so, it is worth noting that its forecasting is getting better and the private forecaster Skymet has also put out a positive forecast for the year, at 102 per cent.
So much is tied to the main southwest monsoon, which covers all of India that a possible success rate close to 60 per cent of the rainfall being above normal this year lends itself easily to a positive scenario. The last time India faced a deficient monsoon was in 2023 and, predictably, IMD had forecast normal rainfall for that season while Skymet had been far less optimistic and declared that it would be a deficient year.
Even so, it is a fact that forecasts are getting more accurate, but maybe not in micro forecasting, which is vital these days because rainfall tends to be far more concentrated in spells and in specific areas than spatially well distributed because of global warming-induced climate change. Alas, droughts and floods have become too common for comfort in these modern times, with climate scientists saying the number of rainy days is declining while heavy rain events are increasing. J&K, Ladakh, Bihar and Tamil Nadu have been warned not to expect above normal rain this monsoon. Of them, Tamil Nadu’s dependence is distributed between the southwest and the northeast monsoons and can hope to have normal rain in the October-December period when the rainfall is confined to the south. A positive forecast ahead of another monsoon season is good for morale and the national mood.
